Grundfos SQE Aids in Subglacial Hydrological Research

Overview

Glacier outbursts are expected to increase, possibly flooding communities living below, as glacier melt and thinning continues to increase during the summer melt season. Even though it is fairly understood how these outbursts occur and there have been model simulations developed to route the flood waters beneath the glacier ice, the models lack field observations from a drainage system standpoint.

Lemon Creek Glacier (LCG) located near Juneau, Alaska was selected by the University of Alberta to undergo field observations investigating the link between the development of the subglacial drainage system and the drainage of a lake at the glaciers surface (supraglacial). Ultimately the study will be the first to measure subglacial hydrological conditions at locations along the glacier length before, during and after a lake drainage event. The data collected will also be used to test and modify model simulations.

Field observations included drilling to LCG ice-bed using a hot-water drill and creating boreholes to perform pumping tests. In order to accomplish this a pump was required that was small enough in diameter to fit down a four inch hole, powerful enough to pump water from depths of 50 to 60 meters and light enough to install, uninstall and move. It also needed to run off a small gasoline generator, have variable pumping rate that could be controlled, all while meeting a small budget.

The SQE has a compact 3-inch design and is equipped with a Grundfos “smart motor” allowing electronic communication with the CU 300 and user. The motor and CU 300 enables variable speed control with the pumps performance being able to adapt to any specific requirement.

The CU 300 communicates with the SQE by power line communication, meaning there are no extra cables required between the controller and the pump.

The SQE has overvoltage and undervoltage protection preventing damage to the motor if the voltage provided by an unstable voltage supply such as a generator happens to move outside the permissible voltage range.

The SQE is protected against dry running, ensuring cut-out of the pump in case of lack of water in the borehole, which will prevent the pump and motor from damage.

The University of Alberta was pleased to find out that the SQE pumping system was able to fulfill all of the requirements on their small budget. In June and July 2011 the University used the SQE to supply water from a nearby stream and lake to the hot-water drill. The SQE was temporarily installed, up to three or four days at a time, where three to six hour pumping tests were performed before the SQE was moved to other boreholes on LCG. The field study was funded by National Geographic Society/Waitt Institute, Canadian Circumpolar Institute, Geological Society of America, The Explorers Club, Arctic Institute of North America, American Alpine Club and Natural Science and Engineering Research Council of Canada. Results from the field study will allow for modifications to model simulations and further analysis.